Semiconductor Device and Method

ABSTRACT

A structure and method for the formation and use of fuses within a semiconductor device is provided. The fuses may be formed within the third metal layer and are formed so as to be arranged perpendicularly to active devices located on an underlying semiconductor substrate. Additionally, the fuses within the third metal layer may be formed thicker than an underlying second metal layer.

PRIORITY CLAIM AND CROSS-REFERENCE

This application is a continuation of U.S. patent application Ser. No.15/170,207 filed on Jun. 1, 2016, entitled “Semiconductor Device andMethod,” which application claims priority to and the benefit of U.S.Provisional Application No. 62/288,799, filed on Jan. 29, 2016, entitled“EFuse Area Reduction and Fuse Connection Current Increasing,” whichapplication is hereby incorporated herein by reference in its entirety.

BACKGROUND

As semiconductor devices decrease in size, each individual componentwithin the semiconductor device should also be reduced in size or itrisks becoming a bottleneck for the further reduction of the device as awhole. For example, as the size of transistors or active devices arereduced, the other parts of the semiconductor device, such as thedielectric layers and metallization layers that provide theinterconnectivity for the active devices, should also see a reduction insize. Otherwise, the overall size of the device may remain the same.

However, reducing the dielectric and metallization layers presents itsown set of problems. For example, as the metallization layers themselvesare scaled down, any devices formed within the metallization layers,such as passive devices including capacitors, resistors, fuses, etc.,would also be scaled down. However, scaling down these types of devicesmay modify their characteristics beyond a desired range of performance.As such, new methods of forming and using the metallization layers anddevices within the metallization layers are desired in order to increasethe miniaturization of these components.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIGS. 1A-1B illustrate a formation of active devices and a first metallayer in accordance with some embodiments.

FIGS. 2A-2B illustrate a formation of a second metal layer in accordancewith some embodiments.

FIGS. 3A-3B illustrate a formation of a third metal layer in accordancewith some embodiments.

FIGS. 4A-4B illustrate a formation of a fourth metal layer in accordancewith some embodiments.

FIGS. 5A-5B illustrate a formation of a fifth metal layer in accordancewith some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. For example, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed between the first and second features, such thatthe first and second features may not be in direct contact. In addition,the present disclosure may repeat reference numerals and/or letters inthe various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

With reference now to FIGS. 1A-1B, wherein FIG. 1B illustrates a topdown view of FIGS. 1A along line B-B′ in FIG. 1A, there is shown aportion of a semiconductor device 100 including a semiconductorsubstrate 101, active devices 103, an interlayer dielectric (ILD) 105, afirst dielectric layer 107, and a first metal layer 109 (M1) within thefirst dielectric layer 107. The semiconductor substrate 101 may comprisebulk silicon, doped or undoped, or an active layer of asilicon-on-insulator (SOI) substrate. Generally, an SOI substratecomprises a layer of a semiconductor material such as silicon,germanium, silicon germanium, SOI, silicon germanium on insulator(SGOI), or combinations thereof. Other substrates that may be usedinclude multi-layered substrates, gradient substrates, or hybridorientation substrates.

The semiconductor substrate 101 may include active devices 103. As oneof ordinary skill in the art will recognize, a wide variety of activedevices and passive devices such as transistors, capacitors, resistors,combinations of these, and the like may be used to generate the desiredstructural and functional requirements of the design for thesemiconductor device 100. The active devices 103 may be formed using anysuitable methods.

In one particular embodiment, the active devices 103 may comprise a gatedielectric (not separately illustrated in FIG. 1A), a gate electrode106, and spacers 108 overlying a channel region (not separatelyillustrated in FIG. 1A) with source/drain regions (also not separatelyillustrated in FIG. 1A) on either side of the gate electrode 106. Thegate dielectric and the gate electrode 106 may be formed and patternedon the semiconductor substrate 101 by any suitable process known in theart. The gate dielectric may be a high-K dielectric material, such assilicon oxide, silicon oxynitride, silicon nitride, an oxide, anitrogen-containing oxide, aluminum oxide, lanthanum oxide, hafniumoxide, zirconium oxide, hafnium oxynitride, a combination thereof, orthe like. Preferably, the gate dielectric has a relative permittivityvalue greater than about 4.

In an embodiment in which the gate dielectric comprises an oxide layer,the gate dielectric may be formed by any oxidation process, such as wetor dry thermal oxidation in an ambient comprising an oxide, H₂O, NO, ora combination thereof, or by chemical vapor deposition (CVD) techniquesusing tetra-ethyl-ortho-silicate (TEOS) and oxygen as a precursor. Inone embodiment, the gate dielectric is between about 8 Å to about 50 Åin thickness, such as about 16 Å in thickness.

The gate electrode 106 comprises a conductive material, such as a metal(e.g., tantalum, titanium, molybdenum, tungsten, platinum, aluminum,hafnium, ruthenium), a metal silicide (e.g., titanium silicide, cobaltsilicide, nickel silicide, tantalum silicide), a metal nitride (e.g.,titanium nitride, tantalum nitride), doped poly-crystalline silicon,other conductive materials, or a combination thereof. In one example,amorphous silicon is deposited and recrystallized to createpoly-crystalline silicon (poly-silicon). In an embodiment in which thegate electrode 106 is poly-silicon, the gate electrode 106 may be formedby depositing doped or undoped poly-silicon by low-pressure chemicalvapor deposition (LPCVD) to a thickness in the range of about 100 Å toabout 2,500 Å, such as about 1,500 Å.

The spacers 108 are formed on sidewalls of the gate dielectric and thegate electrode 106. The spacers 108 are typically formed by blanketdepositing a spacer layer (not shown) on the previously formedstructure. The spacer layer comprises SiN, oxynitride, SiC, SiON, oxide,and the like, and is formed by commonly used methods such as chemicalvapor deposition (CVD), plasma enhanced CVD, sputter, and other methodsknown in the art. The spacer layer is then patterned to form the spacers108, such as by anisotropically etching to remove the spacer layer fromthe horizontal surfaces of the structure.

Source/drain regions are formed in the semiconductor substrate 101 onopposing sides of the gate dielectric. In an embodiment in which thesemiconductor substrate 101 is an n-type substrate, the source/drainregions are formed by implanting appropriate p-type dopants such asboron, gallium, indium, or the like. Alternatively, in an embodiment inwhich the semiconductor substrate is a p-type substrate, thesource/drain regions may be formed by implanting appropriate n-typedopants such as phosphorous, arsenic, or the like. These source/drainregions are implanted using the gate dielectric, gate electrode 106 andthe spacers 108 as masks.

It should be noted that one of ordinary skill in the art will realizethat many other processes, steps, or the like may be used to form thesesource/drain regions. For example, one of ordinary skill in the art willrealize that a plurality of implants may be performed using variouscombinations of spacers and liners to form source/drain regions having aspecific shape or characteristic suitable for a particular purpose. Anyof these processes may be used to form the source/drain regions, and theabove description is not meant to limit the present embodiments to thesteps presented above.

Looking at FIG. 1B, in an embodiment the gate electrode 106 of each ofthe active devices 103 within a first area (represented in FIG. 1B bythe dashed box labeled 102) may be formed so as to extend in the samedirection as each other, and in one particular embodiment the first area102 may be a fuse bit cell area. In an embodiment the first area 102 maybe a region of the semiconductor substrate 101 that will have fusesformed within a third metal layer 301 (not illustrated in FIG. 1B butillustrated and discussed below with respect to FIG. 3). As such, whilethe first area 102 may include the entire semiconductor substrate 101,the first area 102 may also include a subsection of the semiconductorsubstrate 101, such as a region with a first width W₁ of between about200 μm and about 400 μm, such as about 300 μm, and a first length L₁ ofbetween about 100 μm and about 300 μm, such as about 200 μm. However,any suitable dimensions may be utilized.

Additionally in the top down view of FIG. 1B, there are located withinthe first area 102 at least some of the active devices 103. The activedevices 103 that are located within the first area 102 (in this top downview) each have a gate electrode 106 with a first longitudinal axis(represented in FIG. 1B by the dashed line labeled 108) that is parallelwith the other gate electrodes 106 within the first area 102. Further,the first longitudinal axis of each gate electrode 106 within the firstarea 102 extends along a first direction (represented in FIG. 1B by thearrow labeled 111).

Referring back to FIG. 1A, the ILD layer 105 is formed over the activedevices 103 in order to protect and isolate the active devices 103. Inan embodiment the ILD layer 105 may comprise a material such as boronphosphorous silicate glass (BPSG), although any suitable dielectrics maybe used for either layer. The ILD layer 105 may be formed using aprocess such as PECVD, although other processes, such as LPCVD, mayalternatively be used. The ILD layer 105 may be formed to a thickness ofbetween about 100 Å and about 3,000 Å.

Once the ILD layer 105 has been formed, contact plugs 104 may be formedthrough the ILD layer 105 to electrically connect the active devices 103with the overlying first metal layer 109. In an embodiment the formationof the contact plugs 104 may be initiated by first forming contact plugopenings through the ILD layer 105 to expose either the source/drainregions or else the gate electrodes 106 of the active devices 103. In anembodiment the contact plug openings may be formed using a suitablephotolithographic masking and etching process.

Once the contact plug openings have been formed, a formation of a firstglue layer (not separately illustrated in FIG. 1A) may be initiated. Inan embodiment the first glue layer is utilized to help adhere the restof the contact plugs 104 to the underlying structure and may be, e.g.,tungsten, titanium nitride, tantalum nitride, or the like formed using aprocess such as CVD, plasma enhanced chemical vapor deposition (PECVD),physical vapor deposition (PVD), atomic layer deposition (ALD), and thelike or the like.

Once the first glue layer has been formed, the remainder of the contactplugs 104 are formed in contact with the glue layer. In an embodimentthe material of the contact plugs 104 is tungsten (W), although anyother suitable material, such as aluminum, copper, combinations ofthese, or the like, may alternatively be utilized. The material of thecontact plugs 104 may be formed using a process such as CVD, althoughany suitable process, such as PECVD, physical vapor deposition (PVD),atomic layer deposition (ALD), and the like, may alternatively beutilized.

Once filled, a planarization of the contact plugs 104 is performed suchthat the material of the contact plugs 104 that is outside of the ILDlayer 105 is removed, forming the contact plugs 104 (one of which isillustrated in FIG. 1A). In an embodiment the planarization process is achemical mechanical polish (CMP), in which a combination of etchingmaterials and abrading materials are put into contact with the materialof the contact plugs 104 and a grinding pad (not separately illustrated)is used to grind away the material of the contact plugs 104 until all ofthe material of the contact plugs 104 over the first dielectric layer105 has been removed.

The first dielectric layer 107 may be formed over the ILD layer 105. Thefirst dielectric layer 107 may be made of one or more suitabledielectric materials such as low-k dielectrics such as carbon dopedoxides, extremely low-k dielectrics such as porous carbon doped silicondioxide, silicon oxide, silicon nitride, a polymer such as polyimide,combinations of these, or the like. The first dielectric layer 107 maybe formed through a process such as a spin-on process or a chemicalvapor deposition (CVD), although any suitable process may be utilized,and may have a first thickness T₁ of between about 400 Å and about 1000Å, such as about 600 Å.

FIGS. 1A-1B additionally illustrate a formation of the first metal layer109 within the first dielectric layer 107. In an embodiment the firstmetal layer 109 may be formed using, e.g., a damascene process, wherebyan opening is first formed within the first dielectric layer 107. In anembodiment the opening may be formed by first placing and patterning aphotoresist material over the first dielectric layer 107. Once thephotoresist material has been placed and patterned, a dry etch processsuch as a reactive ion etch may be utilized to transfer the pattern fromthe patterned photoresist to the underlying first dielectric layer 107.

Once the desired pattern has been transferred, the opening may be filledwith a conductive material in order to form the first metal layer 109within the first dielectric layer 107. In an embodiment the formation ofthe conductive material may be initiated by first depositing a barrierlayer (not separately illustrated in FIGS. 1A-1B). The barrier layer maybe a barrier material such as titanium nitride or tantalum nitride whichmay be deposited using a deposition process such as chemical vapordeposition, physical vapor deposition, atomic layer deposition, or thelike. However, any suitable material or method of deposition may beutilized to form the barrier layer.

Once the barrier layer has been formed, a conductive material may bedeposited to fill and/or overfill the openings within the firstdielectric layer 107. In an embodiment the conductive material may be amaterial such as copper, aluminum, or tungsten, formed, e.g., using aseed layer (not shown) and a plating process, such as electrochemicalplating, although other processes of formation, such as sputtering,evaporation, or a PECVD process, may alternatively be used dependingupon the desired materials. Once the openings for the first metal layer109 have been filled with conductive material, any excess conductivematerial outside of the openings for the first metal layer 109 may beremoved, and the first metal layer 109 and the first dielectric layer107 may be planarized using, for example, a chemical mechanicalpolishing process. Additionally, because all of the excess conductivematerial is removed from outside of the openings, the first metal layer109 will also have the same thickness as the first dielectric layer 107,such as by having the first thickness T₁.

Looking back at FIG. 1B, the first metal layer 109 is utilized tointerconnect the various active devices 103 (through the contact plugs104) and routes the connections as desired in order to form thefunctional requirements for the semiconductor device 100. Additionally,each of the individual conductive lines within the first metal layer 109within the first area 102 has a second longitudinal axis (represented inFIG. 1B by the dashed line labeled 110) that is parallel with the otherconductive lines within the first metal layer 109 within the first area102. Additionally, the second longitudinal axis 110 run in a seconddirection (represented in FIG. 1B by the arrow labeled 113) that isperpendicular to the first direction 111. As such, the first metal layer109 is aligned perpendicular with the gate electrodes 106 of the activedevices 103.

FIGS. 2A-2B illustrate a cross-sectional view and a top down view,respectively, with FIG. 2B illustrating a top down view of FIG. 2A alongline B-B′, of the semiconductor device 100 after the formation of asecond metal layer 201 (M2) within a second dielectric layer 203. In anembodiment the second dielectric layer 203 may be initially formed priorto the second metal layer 201, and the second dielectric layer 203 maybe formed as discussed above with respect to the first dielectric layer107. For example, the second dielectric layer 203 may be a low-kdielectric material formed using a spin on process. However, in thisprocess the second dielectric layer 203 may be formed to have a secondthickness T₂ of between about 1000 Å and about 2000 Å, such as about1300 Å.

Once the second dielectric layer 201 has been formed, the second metallayer 201 may be formed within the second dielectric layer 203. In anembodiment the second metal layer 201 may be formed, e.g., by firstforming openings for the second metal layer 201 into the seconddielectric layer 203 using, e.g., a dual damascene process whichutilizes two photolithographic masks and two etching processes to formboth a lower via portion as well as an upper trench portion. In anembodiment the openings for the second metal layer 201 may be initiatedusing a first mask along with a first etching process in order to formthe shape of the lower via portion of the second metal layer 201(separated from the upper portion of the second metal layer 201 in FIG.2A by the dashed line 205).

In an embodiment the first mask may be a photoresist that has beenplaced using, e.g., a spin on process. Once in place, the photoresistmay then be exposed to a patterned light source and developed in orderto form a patterned photoresist into the desired pattern for the lowervia portion of the second metal layer 201. However, the first mask mayalternatively be a hard mask such as silicon nitride. Any suitablemasking material and any process of patterning the masking material mayalternatively be utilized.

Once the first mask has been placed and patterned, the pattern of thefirst mask may be transferred to the second dielectric layer 203. In anembodiment a directional etching process such as a reactive ion etch maybe utilized to remove the material of the second dielectric layer 203while using the first mask as a mask during the etching. As such, onlyexposed and unprotected material is removed, thereby transferring thepattern of the first mask into the second dielectric layer 203.

Once the pattern of the first mask has been transferred to the seconddielectric layer 203, the first mask may be removed. In an embodiment inwhich the first mask is a photoresist, the first mask may be removedusing, e.g., an ashing process, whereby the temperature of the firstmask is increased until a thermal decomposition occurs, whereby thephotoresist may be removed. However, any other suitable method ofremoval, such as a wet etching process, may alternatively be utilized.

Once openings for the lower via portions of the second metal layer 201have been shaped, the openings for the lower via portions may beextended at the same time as upper trench portions are formed within thesecond dielectric layer 203. In an embodiment, once the lower portionsof the second metal layer 201 have been shaped by the first mask andetch, a second mask and a second etching process may be used to extendthe openings for the second metal layer 201 to the first metal layer 109as well as form the upper trench portion of the second metal layer 201where the second metal layer 201 will be used to route the electricalsignals, power, and ground connections.

The second mask may be similar to the first mask as discussed above. Forexample, the second mask may be a photoresist that has been patterned byexposing and developing a layer of photoresist composition (notindividually illustrated) into the desired pattern for the upper trenchportions of the second metal layer 201. However, the second mask mayalternatively be a hard mask such as silicon nitride. Any suitablemasking material and any process of patterning the masking material mayalternatively be utilized.

Once the second mask has been placed and patterned, the pattern of thesecond mask may be transferred to the second dielectric layer 203. In anembodiment a directional etching process such as a reactive ion etch maybe utilized to remove the material of the second dielectric layer 203while using the second mask as a mask during the etching. As such, onlyexposed and unprotected material is removed, thereby transferring thepattern of the second mask into the second dielectric layer 203. Thisprocess forms the widened upper trench portions of the second metallayer 201 as well as extending the shape of the lower portions of thesecond metal layer 201 through the second dielectric layer 203 in orderto expose the first metal layer 109.

Once finished, the second mask may be removed and the openings filled toform the second metal layer 201. In an embodiment in which the secondmask is a photoresist, the second mask may be removed using, e.g., anashing process, whereby a temperature of the material of the second maskis increased until the material of the second mask thermally decomposesand may be removed. However, any suitable removal process, such asetching or applying a suitable solvent, may alternatively be utilized.

After the second mask has been removed, the second metal layer 201 maybe formed within both the lower via portion as well as the upper trenchportion using a first seed layer (not shown) and a plating process, suchas electrochemical plating, although other processes of formation, suchas sputtering, evaporation, or PECVD process, may alternatively be useddepending upon the desired materials. The second metal layer 201 maycomprise copper, but other materials, such as aluminum or tungsten, mayalternatively be used. Once the openings for the second metal layer 201have been filled with conductive material, any excess conductivematerial outside of the openings for the second metal layer 201 may beremoved, and the second metal layer 201 and the second dielectric layer203 may be planarized using, for example, a chemical mechanicalpolishing process.

In an embodiment, the lower via portion of the second metal layer 201may be formed to have a third thickness T₃ of between about 400 Å andabout 800 Å, such as about 500 Å. Additionally, the upper via portion ofthe second metal layer 201 may be formed to have a fourth thickness T₄that is greater than the first thickness T₁, such as being between about600 Å and about 1200 Å, such as about 800 Å. However, any suitablethicknesses may be utilized to form the second metal layer 201.

FIG. 2B, which illustrates a top down view of the structure of FIG. 2A,illustrates that, within the first area 102 of the second metal layer201, the individual lines of the second metal layer 201 (e.g., the uppertrench portion) will have third longitudinal axes (represented in FIG.2B by the dashed line labeled 207) that are parallel with each other.Further, these third longitudinal axes 207 are aligned in the firstdirection 111. As such, the individual lines of the second metal layer201 are aligned in the same direction as the gate electrodes 106 of theactive devices 103.

FIGS. 3A-3B illustrate a formation of a third metal layer 301 (M3) and athird dielectric layer 303 over the second metal layer 201, with FIG. 3Billustrating a top down view of FIG. 3A along line B-B′. In anembodiment the third dielectric layer 303 may be formed using similarmethods and materials as described above with respect to the seconddielectric layer 203. For example, the third dielectric layer 303 may bea low-k dielectric material formed using a spin on process. However, anysuitable process may be utilized to form the third dielectric layer 303.The third dielectric layer 303 may be formed to a fifth thickness T₅ ofbetween about 800 Å and about 1400 Å, such as about 1100 Å.

Once the third dielectric layer 303 has been formed, the third metallayer 301 may be formed within the third dielectric layer 303. In anembodiment the third metal layer 301 may be formed using similarprocesses and similar materials as described above with respect to thesecond metal layer 201. For example, a dual damascene, two step processmay be used to initially form a first opening into the third dielectriclayer 303 and then extend the first opening through the third dielectriclayer 303 to form a lower via opening while at the same time forming asecond opening into, but not through, the third dielectric layer 303 foran upper trench opening. Once the openings have been formed, aconductive material such as copper may be deposited to fill and/oroverfill the openings, and any excess conductive material may be removedfrom outside of the openings using a planarization process. However, anysuitable method of manufacturing may be utilized to form the third metallayer 301.

In an embodiment the upper trench portions of the third metal layer 301have a sixth thickness T₆ that is less than the fourth thickness T₄ (ofthe second metal layer 201), such as by being between about 400 Å andabout 1000 Å, such as about 600 Å. Additionally, the lower via portionsof the third metal layer 301 may be formed to have a seventh thicknessT₇ of between about 400 Å and about 800 Å, such as about 500 Å. However,any suitable thicknesses may be utilized.

By forming the upper trench portions of the third metal layer 301 tohave the sixth thickness T₆ that is less than the fourth thickness T₄,the overall resistance that is encountered during programming of thefuses may be reduced. In particular, in an embodiment in which thesecond metal layer 201 is thicker than the third metal layer 301, thelower resistance of the second metal layer 201 leads to an increase inthe fuse connection current that may be supplied by the connections ofthe second metal layer 201 to the fuses within the third metal layer 301(e.g., the first fuse 307, the second fuse 309, and the third fuse 311).

FIG. 3B, which illustrates a top down view of the structure of FIG. 3A,illustrates that, within the first area 102 of the third metal layer301, the individual lines have third longitudinal axes (represented inFIG. 2B by the dashed line labeled 305) that are all parallel with eachother. Additionally, the third longitudinal axes 305 are also aligned inthe second direction 113. As such, the third metal layer 301 is alignedwith the first metal layer 109 and is also aligned perpendicular withthe gate electrodes 106 of the active devices 103 as well as alignedperpendicular with the second metal layer 201 and the gate electrodes106 of the active devices 103. By forming the third longitudinal axes305 to be perpendicular with the gate electrodes, the structure islithography friendly.

FIG. 3B additionally illustrates a formation of fuses (e.g., a firstfuse 307, a second fuse 309, and a third fuse 311) within the thirdmetal layer 301. In an embodiment the first fuse 307, the second fuse309 and the third fuse 311 are formed within the third metal layer 301by adjusting the thickness of portions of the individual lines of thethird metal layer 301 using, e.g., the masking and etching processesduring the formation of the openings for the third metal layer 301. Forexample, in one particular embodiment in which the individual lines ofthe third metal layer 301 within the first area 102 have a second widthW₂ of between about 350 Å and about 550 Å, such as about 450 Å, thefirst fuse 307 may be formed to have a third width W₃ that is less thanthe second fuse 309 and the third fuse 311, such as by being betweenabout 200 Å and about 400 Å, such as about 300 Å. Additionally, thesecond fuse 309 may be formed to have a fourth width W₄ that is largerthan the first fuse 307 and less than the third fuse 311, such as bybeing between about 250 Å and about 450 Å, such as about 350 Å. Finally,the third fuse 311 may be formed to have a fifth width W₅ that is largerthan both the first fuse 307 and the second fuse 309, such as by beingbetween about 300 Å and about 500 Å, such as about 400 Å. However, anysuitable dimensions may be utilized.

Additionally, while only three fuses are illustrated in FIG. 3B, theseare intended to be representative and not limiting to the embodiments.Rather, any suitable number of fuses (greater than, equal to, or lessthan the number illustrated) may be utilized, and all such number arefully intended to be included within the scope of the embodiments.

By forming the fuses (e.g., the first fuse 307, the second fuse 309, andthe third fuse 311) within the third metal layer 301 without additionalrouting and by forming the fuses not within the first metal layer 109,not within the second metal layer 201 (which has routing), or within theoverlying metal layers (described further below) the first area 102which contains the fuses may be reduced in size as the routing that maybe needed in the second metal layer 201 (in addition to the fuses) maybe removed. For example, the first area 102 may be reduced in size (in atop down view) to have an area between about 20000 μm² and about 120000μm², such as about 60000 μm². By reducing the size of the first area 102which comprises the fuses, the overall size of the semiconductor device100 may be reduced as well.

FIGS. 4A-4B illustrate a formation of a fourth metal layer 401 (M4)within a fourth dielectric layer 403. In an embodiment the fourthdielectric layer 403 may be formed using similar methods and materialsas described above with respect to the second dielectric layer 203. Forexample, the fourth dielectric layer 403 may be a low-k dielectricmaterial formed using a spin on process to an eighth thickness T₈ ofbetween about 1000 Å and about 2000 Å, such as about 1300 Å. However,any suitable process and any suitable thickness may be utilized to formthe fourth dielectric layer 403.

Once the fourth dielectric layer 403 has been formed, the fourth metallayer 401 may be formed within the fourth dielectric layer 403. In anembodiment the fourth metal layer 401 may be formed using similarprocesses and similar materials as described above with respect to thesecond metal layer 201. For example, a dual damascene, two-step processmay be used to initially form a first opening for a lower via portioninto the fourth dielectric layer 403 and then extend the first openingthrough the fourth dielectric layer 403 while at the same time forming asecond opening into, but not through, the fourth dielectric layer 403for an upper trench portion of the fourth metal layer 401. Once theopenings have been formed, a conductive material such as copper may bedeposited to fill and/or overfill the openings, and any excessconductive material may be removed from outside of the openings using aplanarization process. However, any suitable method of manufacturing maybe utilized to form the fourth metal layer 401.

In an embodiment the upper trench portion of the fourth metal layer 401may be formed to have a ninth thickness T₉ of between about 600 Å andabout 1200 Å, such as about 800 Å. Additionally, the lower via portionmay have a tenth thickness T₁₀ of between about 400 Å and about 800 Å,such as about 500 Å. However, any suitable thickness may be utilized toform the upper trench portion of the fourth metal layer 401 and thelower via portion of the fourth metal layer 401.

FIG. 4B, which illustrates a top-down view of the structure of FIG. 4Aalong line B-B′ (with the active devices 103 additionally illustrated bydashed lines for convenience), illustrates that, within the fourth metallayer 401, the individual lines of the fourth metal layer 401 (e.g., theupper trench portions of the fourth metal layer 401) have fifthlongitudinal axes (represented in FIG. 4B by the dashed line labeled405) that are aligned with each other. Further, the fifth longitudinalaxes 405 are also aligned in the first direction 111. As such, thefourth metal layer 401 is aligned parallel with the second metal layer201 as well as the gate electrodes 106 of the active devices 103.Additionally, the fourth metal layer 401 is perpendicular with the thirdmetal layer 301 and the first metal layer 109.

FIGS. 5A-5B illustrate a formation of a fifth metal layer 501 (M5)within a fifth dielectric layer 503, with FIG. 5B illustrating a topdown view of FIG. 5A along line B-B′. In an embodiment the fifthdielectric layer 503 may be formed using similar methods and materialsas described above with respect to the second dielectric layer 203. Forexample, the fifth dielectric layer 503 may be a low-k dielectricmaterial formed using a spin on process to an eleventh thickness T₁₁ ofbetween about 2000 Å and about 4000 Å, such as about 3000 Å. However,any suitable process may be utilized to form the fifth dielectric layer503.

Once the fifth dielectric layer 503 has been formed, the fifth metallayer 501 may be formed within the fifth dielectric layer 503. In anembodiment the fifth metal layer 501 may be formed using similarprocesses and similar materials as described above with respect to thesecond metal layer 201. For example, a dual damascene, two step processmay be used to initially form a first opening into the fifth dielectriclayer 503 for the lower via portion of the fifth metal layer 501 andthen extend the first opening through the fifth dielectric layer 503while at the same time forming a second opening into, but not through,the fifth dielectric layer 503 for the upper trench portion of the fifthmetal layer 501. Once the openings have been formed, a conductivematerial such as copper may be deposited to fill and/or overfill theopenings, and any excess conductive material may be removed from outsideof the openings using a planarization process. However, any suitablemethod of manufacturing may be utilized to form the fifth metal layer501.

FIG. 5B, which illustrates a top-down view of the structure of FIG. 5A(with the active devices 103 additionally illustrated by dashed linesfor convenience), illustrates that, within the first area 102 of thefifth metal layer 501, the individual lines of the fifth metal layer 501(e.g., the upper trench portions of the fifth metal layer 501) havesixth longitudinal axes (represented in FIG. 5B by the dashed linelabeled 505) that are aligned with each other. Further, the sixthlongitudinal axes 505 are also aligned in the second direction 113. Assuch, the fifth metal layer 501 is aligned perpendicular with the secondmetal layer 201 as well as the gate electrodes 106 of the active devices103. Additionally, the fifth metal layer 501 is parallel with the thirdmetal layer 301 and the first metal layer 109.

Once the fifth metal layer 501 has been formed, the semiconductor device100 may be completed by forming contact pads, passivation layers, andexternal connectors that can connect the semiconductor device 100 tooutside devices (all of which are not separately illustrated in theFigures), as well as the semiconductor device 100 being singulated froma wafer on which it was formed. Additionally, any suitable additionalstructures, packages, or other external devices may be utilized andconnected to the semiconductor device 100 to prepare the semiconductordevice 100 for eventual consumer usage.

Additionally, once the semiconductor device 100 is ready to be utilized,the semiconductor device 100 may be programmed in order to blow certainones of the fuses (e.g., the first fuse 307, the second fuse 309, andthe third fuse 311) in order to program the semiconductor device 100. Inan embodiment the first fuse 307, the second fuse 309, and the thirdfuse 311 may be sequentially blown using, e.g., an EFUSE process,although any suitable process may be utilized. For example, in anembodiment in which an EFUSE process is utilized, a voltage is appliedto the third metal layer 301 (through, e.g., the second metal layer 201)of between about 1.6 V and about 2.0 V, such as about 1.8 V, for aperiod of time between about 2 μs and about 10 μs, such as about 6 μs.This voltage, when applied to the third metal layer 301 with thedimensions as described above, will sequentially blow the first fuse 307(with the smallest width), then blow the second fuse 309 (with themiddle width) and then, finally, blow the third fuse 311. As such, bycontrolling the voltage as well as the amount of time that theprogramming current is applied to the fuses, a controlled programmingprocess that will sequentially blow the fuses may be used to blow onefuse (e.g., the first fuse 307), two of the fuses (e.g., the first fuse307 and the second fuse 309), or all three of the fuses (e.g., the firstfuse 307, the second fuse 309, and the third fuse 311). As such, thesemiconductor device 100 may be programmed as desired.

However, by manufacturing the metal layers and the fuses as describedherein, the overall programming current that is used to program thefuses within the third metal layer 301 may be increased because of thereduction in resistance through the increased thickness of the secondmetal layer 201, which supplies the programming current to the thirdmetal layer 301. As such, the programming current applied to the thirdmetal layer 301 may be between about 20 μA and about 100 μA, such asabout 60 μA. However, any suitable programming current may be applied.

In accordance with an embodiment, a method of manufacturing asemiconductor device comprising forming a plurality of gate electrodesover a first region of a semiconductor substrate, the plurality of gateelectrodes extending in a first direction is provided. A first metallayer is formed over the plurality of gate electrodes in the firstregion, wherein each individual line in the first metal layer within thefirst region extends in a second direction perpendicular with the firstdirection, wherein the first metal layer is free from fuses. A secondmetal layer is formed over the first metal layer in the first region,wherein each individual line in the second metal layer within the firstregion extends in the first direction, wherein the second metal layer isfree from fuses. A third metal layer is formed over the second metallayer in the first region, wherein each individual line in the thirdmetal layer within the first region extends in the second direction,wherein the third metal layer comprises fuses.

In accordance with another embodiment, a method of manufacturing asemiconductor device comprising forming a series of active devices on asemiconductor substrate is provided. A first metal layer is depositedover the series of active devices, the first metal layer being arrangedperpendicular to the series of active devices in a top down view. Asecond metal layer is deposited over the first metal layer, the secondmetal layer being arranged perpendicular to the first metal layer in thetop down view, and a series of fuses is deposited within a third metallayer over the second metal layer, the third metal layer being arrangedperpendicular to the second metal layer in the top down view.

In accordance with yet another embodiment, a semiconductor devicecomprising a plurality of active devices in a first area of asemiconductor substrate, the plurality of active devices extending in afirst direction is provided. A first metal layer is over the pluralityof active device, the first metal layer comprising a first plurality ofmetal lines in the first area arranged in a second directionperpendicular to the first direction, and a second metal layer is overthe first metal layer, the second metal layer comprising a secondplurality of metal lines in the first area arranged in the firstdirection. A third metal layer is over the second metal layer, the thirdmetal layer comprising a third plurality of metal lines and a pluralityof fuses, wherein the third plurality of metal lines are arranged in thesecond direction.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A semiconductor device comprising: a plurality ofgate electrodes over a first region of a semiconductor substrate, theplurality of gate electrodes extending in a first direction; a firstmetal layer over the plurality of gate electrodes in the first region; asecond metal layer over the first metal layer in the first region; and athird metal layer over the second metal layer in the first region,wherein each individual line in the third metal layer within the firstregion extends in a second direction perpendicular with the firstdirection, wherein the third metal layer comprises fuses.
 2. Thesemiconductor device of claim 1, wherein each individual line in thefirst metal layer within the first region extends in a second directionperpendicular with the first direction, wherein the first metal layer isfree from fuses.
 3. The semiconductor device of claim 2, wherein eachindividual line in the second metal layer within the first regionextends in the first direction, wherein the second metal layer is freefrom fuses.
 4. The semiconductor device of claim 1, further comprising afourth metal layer over the third metal layer in the first region,wherein each individual line in the fourth metal layer within the firstregion extends in the first direction.
 5. The semiconductor device ofclaim 4, further comprising a fifth metal layer over the fourth metallayer in the first region, wherein each individual line in the fifthmetal layer within the first region extends in the second direction. 6.The semiconductor device of claim 1, wherein the second metal layer hasa first thickness and wherein the third metal layer has a secondthickness different from the first thickness.
 7. The semiconductordevice of claim 6, wherein the second thickness is less than the firstthickness.
 8. A semiconductor device comprising: a series of activedevices on a semiconductor substrate; a first metal layer over theseries of active devices; a second metal layer over the first metallayer; and a series of fuses within a third metal layer over the secondmetal layer, the third metal layer being arranged perpendicular to theseries of active devices in a top down view.
 9. The semiconductor deviceof claim 8, wherein the first metal layer is arranged perpendicular tothe series of active devices in a top down view.
 10. The semiconductordevice of claim 9, wherein the second metal layer is arrangedperpendicular to the first metal layer in the top down view.
 11. Thesemiconductor device of claim 8, wherein the series of fuses has a firstthickness and wherein the second metal layer has a second thicknessdifferent from the first thickness.
 12. The semiconductor device ofclaim 11, wherein the first thickness is less than the second thickness.13. The semiconductor device of claim 8, further comprising a fourthmetal layer over the third metal layer, the fourth metal layer beingarranged perpendicular to the third metal layer in the top down view.14. The semiconductor device of claim 8, further comprising a fifthmetal layer over the fourth metal layer, the fifth metal layer beingarranged perpendicular to the fourth metal layer in the top down view.15. A method of manufacturing a semiconductor device comprising: forminga plurality of active devices in a first area of a semiconductorsubstrate, the plurality of active devices extending in a firstdirection; depositing a first metal layer over the plurality of activedevice; depositing a second metal layer over the first metal layer; andforming a third metal layer over the second metal layer, the third metallayer comprising a third plurality of metal lines and a plurality offuses, wherein the third plurality of metal lines are arranged in asecond direction perpendicular to the first direction.
 16. The method ofclaim 15, wherein the first metal layer comprising a first plurality ofmetal lines in the first area arranged in the second direction.
 17. Themethod of claim 16, wherein the second metal layer comprises a secondplurality of metal lines in the first area arranged in the firstdirection.
 18. The method of claim 17, further comprising forming afourth metal layer over the third metal layer, the fourth metal layercomprising a fourth plurality of metal lines arranged in the firstdirection.
 19. The method of claim 15, wherein the third plurality ofmetal lines has a first thickness, the second metal layer has a secondthickness, and the first thickness is less than the second thickness.20. The method of claim 15, wherein the first metal layer and the secondmetal layer are the only metallization layers between the active devicesand the third metal layer.